NEW YORK, U.S. - At the end of a fiery and divisive campaign for the U.S. Congressional elections, that is being widely seen as a referendum on the U.S. President Donald Trump and his presidency, Americans headed to the polls on Tuesday.

With all the 435 seats in the U.S. House of Representatives, along with 35 of 100 seats in the Senate and 36 governorships up for re-election - American votes will deliver a judgement on not just the critical power balance in the U.S. Congress, but also on the future of Trump's administration and his policies.

With Democrats campaigning to end the Republican monopoly in Washington and state legislatures across the country, and Republicans fighting hard to retain dominance in both the houses of the Congress - the midterm election has been marked by a strong and divisive campaign and is therefore expected to witness high voter turnout.

Democrats are hoping to hamper the implementation of Trump's hardline policies by seizing control of one of both chambers, while Republicans hope to maintain power in both the Senate and the House of Representatives, so as to build on the President's agenda.

Both the sides have spent billions of dollars on campaigning material and the final day of campaigning witnessed an embarrassing controversy for the GOP after several networks and media houses pulled an ad by Trump's campaign.

NBC, CNN, Fox News and Facebook dropped a 30-second spot by the Trump campaign that was labelled as racially divisive by critics and some members of Trump's own party.

The ad featured a courtroom video of an illegal immigrant from Mexico, who was convicted in the 2014 killings of two police officers, alongside scenes of migrants headed through Mexico.

Turnout and early ballots

According to the U.S. Elections Project, a University of Florida-based information source, about 34.3 million people have cast early ballots but the real number is believed to be much higher.

Estimates further stated that in Texas, early voting exceeded the entire turnout in 2014 - which still at 27.5 million.

Earlier this week, weather forecasts suggested thunderstorms along the eastern coast for Tuesday and snowstorms were predicted in the Midwest, which were set to affect turnout.

However, experts are predicting that voter turnout could be the highest for a midterm election in half a century.

Late on Monday evening, the Utah Elections Office released an update showing that even before Election Day, Utahs voter turnout for the midterm had exceeded the turnout from the last midterm.

The update stated that in 2014s midterm election, Utah ended up with a voter turnout of 46.25 percent.

Utah County Clerk Bryan Thompson said in a statement, For a midterm general election, there is a lot of enthusiasm and a lot more interest in this election than Ive seen in many years."

He added that he predicts turnout for Utah County to approach 60 percent.

On Tuesday, polls finally opened first on the East Coast, with voters in Maine, New Hampshire, New York, New Jersey and Virginia lining up early at polling booths.

In Kentucky, the first polls will close at 18.00 EST (23.00 GMT), and analysts are eyeing the state closely as it could provide some early indications of the direction of the race.

Fiery final pitches

On the final day of campaigning, Trump delivered fiery speeches at three final campaign rallies, in Ohio, Indiana and Missouri.

The President reiterated key campaign issues and stressed on his message of fear, pointing out that Democrats would damage the economy and bolster illegal immigration that he is fighting hard against.

Meanwhile, Democrats focused on healthcare and economic inequality and hoped that the vast young and suburban population that has raised its voice against Trump's rhetoric will convert into positive poll numbers.

While Trump's final message to his supporters was that, "Everything we have achieved is at stake tomorrow," the former U.S. President Barack Obama - who has been on the campaign trail for the Democratic party - declared at a rally that "the character of our country is on the ballot."

Obama tweeted that the vote "might be the most important of our lifetimes."